3D model-assisted instrumentation of the pediatric spine: a technical note

Abstract

Background: Instrumentation of the pediatric spine is challenging due to anatomical constraints and the absence of specific instrumentation, which may result in iatrogenic injury and implant failure, especially in occipito-cervical constructs. Therefore, preoperative planning and in vitro testing of instrumentation may be necessary.

Methods: In this paper, we present a technical note on the use of 1:1 scale patient-specific 3D printed spinal models for preoperative assessment of feasibility of spinal instrumentation with conventional spinal implants in pediatric spinal pathologies.

Results: The printed 3D models fully matched the intraoperative anatomy and allowed a preoperative confirmation of the feasibility of the planned instrumentation with conventional screws for adult patients. In addition, the possibility of intraoperative model assessment resulted in better intraoperative sense of spinal anatomy and easier freehand screw insertion, thereby reducing the potential for iatrogenic injury. All 3D models were printed at the surgical department at a very low cost, and the direct communication between the surgeon and the dedicated specialist allowed for multiple models or special spinal segments to be printed for more detailed consideration.

Conclusions: Our technical note highlights the critical steps for preoperative virtual planning and in vitro testing of spinal instrumentation on patient-specific 3D printed models at 1:1 scale. The simple and affordable method helps to better visualize pediatric spinal anatomy and confirm the suitability of preplanned conventional spinal instrumentation, thereby reducing X-ray exposure and intraoperative complications in freehand screw insertion without navigation.

Keywords: 3D printed model; In vitro testing; Pediatric spinal instrumentation; Virtual preoperative planning.

Fig. 1

a 3D virtual model of spine and occiput anatomy. b Simulation of screw positioning. c Virtual verification of screws dimensions and the bone stock in the cutaway mode relative to the screw axis. d X-ray simulation of the positions of screws

Fig. 2

a Performing in vitro operation on a 3D printed spine and occiput model. b Measuring the occiput region. c Instrumentation in place on the 3D model. d Verifying that the measurement in the 3D virtual operation was correct

Fig. 3

a X-ray simulation in preoperative planning software. b Intraoperative CT verification. c Postoperative control X-ray in HALO jacket

Fig. 4

a Virtual 3D preoperative planning of the instrumentation. b In vitro positioning of the implants. c Operation with the 3D model on display. d Intraoperative image intensifier control